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201. 题目: Abundance of phytanyl and n-alkyl toluenes in petroleum from the Lower Saxony Basin (Germany) provides information on maturity, palaeosettings and sources
文章编号: N25052708
期刊: Organic Geochemistry
作者: Georg Scheeder, Christian Ostertag-Henning, Martin Blumenberg
更新时间: 2025-05-27
摘要: Alkyl benzenes and toluenes are common in petroleum and shales. In addition to the series of n-alkylated benzenes and toluenes, the phytanyl toluene (and −benzene) is often abundant. In the present study, n-alkyl toluenes and phytanyl toluene were detected in more than 180 petroleum oils with different maturation histories and from two different source rocks, the Jurassic Posidonia Shale and the Cretaceous Wealden Shale (from the Lower Saxony Basin; Germany). A novel ratio of C22-C24meta-substituted n-alkyl (combined in the ratio as “n”) to phytanyl (“iso”) toluenes is proposed as a thermal maturity indicator. Our data show that the relative proportion of phytanyl toluene to n-alkyl toluenes systematically decreases with maturity and therefore the “n/(n + iso)” toluene index increases. The relative change is due to both the processes of catalytic formation of n-alkyl toluenes and destruction of phytanyl toluene. The applicability of this ratio was confirmed using closed gold capsule pyrolysis maturation experiments with Posidonia Shale (for a maturation range from EASY%Ro of 0.78 to 1.4 %). The correlation is most pronounced in petroleum produced from the Posidonia Shale. For oils from the Wealden shales, the correlation is less clear due to the generally low phytanyl toluene contents. Comparisons of the “n/(n + iso)” toluene index with maturity-dependent biomarker ratios indicated its potential to record thermal maturity over a wide range. The occurrence of phytanyl toluene also appears to record a poorly understood (microbial) source, which was more abundant in the marine-euxinic depositional system of the Posidonia Shale than that of the brackish-marine Wealden shales.

202. 题目: Nanoscale and molecular evidences for adsorptive fractionation of dissolved organic matter at the interfaces of Al-bearing ferrihydrite and water
文章编号: N25052707
期刊: Water Research
作者: Li Li, Hanyue Zhang, Xiaojuan Li, Shiwen Hu
更新时间: 2025-05-27
摘要: Ferrihydrite (Fh) usually exists in the form of Al-bearing Fh in soils and sediments, and Al substitution may have a remarkable influence on Fh characteristics, controlling its reaction with dissolved organic matter (DOM). Yet, little is known about the impacts of Al-bearing Fh on the fate of DOM. Here, selective binding and molecular fractionation of DOM was investigated at the interfaces of Al-bearing Fh and water. Al substitution altered surface properties such as point of zero charge (PZC), surface OH groups, and specific surface areas (SSA), structure, composition, and adsorption capacity of Fh. Specifically, within 30 mol% Al substitution, Al entered into ferrihydrite structure by isomorphous substitution to form Al-substituted ferrihydrite and immobilized DOM increased with Al substitution owing to increasing surface OH groups, SSA, and pore volumes. Once the amount of added Al exceeds 30 mol%, gibbsite was formed except for Al-substituted Fh, and adsorbed DOM decreased with Al addition. The coordination environment of Al-substituted Fh consisted of Fe-O and edge- and corner-sharing FeO₆ octahedral. Microscopic analysis at nanoscale disclosed that DOM was evenly distributed within Al-bearing Fh aggregates and on gibbsite surface, and DOM immobilized within Al-bearing Fh nanopores had a higher oxidation state. Mass spectrometry analysis at molecular scale revealed that compared with gibbsite, high molecular weight substances and substances containing more oxygenated groups or highly in unsaturation preferentially bound to Al-bearing Fh, and Fh with 30 mol% Al substitution induced most pronounced molecular fractionation. Collectively, these findings shed novel insights into the impact of Al substitution on interfacial adsorptive fractionation of DOM, contributing to in-depth understanding geochemical cycling of C and predicting organic C cycling across aquatic-terrestrial interfaces.

203. 题目: Harnessing conductive materials for sustainable food waste treatment: Comparative evaluation of biochar and magnetite in volatile fatty acid production
文章编号: N25052706
期刊: Journal of Environmental Management
作者: Xiong Zheng, Zhengzheng Zhao, Zizeng Zhu, Yang Wu, Min Long, Yinguang Chen
更新时间: 2025-05-27
摘要: Anaerobic fermentation offers a sustainable and eco-friendly approach to converting food waste (FW) into high-value volatile fatty acids (VFAs). Although both carbon- and metal-based conductive materials can enhance VFAs yields during FW fermentation, a comprehensive comparison of these materials and their underlying mechanisms remains unexplored, limiting their practical selection and application. This study systematically investigated the differences between biochar and magnetite, which are representative carbon- and metal-based conductive materials, in promoting VFAs production during FW fermentation. The results indicated that VFAs yields increased by 106 % and 81.2 % in the presence of biochar and magnetite, respectively, compared to the control, with notable enhancements during critical fermentation stages, including solubilization, hydrolysis, and acidification. Microbial analysis demonstrated that biochar more effectively enriched electroactive bacteria with acid-forming functions (e.g., Clostridium was enriched 1.3-fold more than in the control) compared to magnetite. Additionally, biochar more efficiently upregulated metabolic pathways associated with VFAs biosynthesis, including pyruvate metabolism (e.g., aceE and pckA), acetate production (e.g., pta and acyP), and butyrate production (e.g., ptb and bok). Biochar also enhanced microbial adaptability to external environmental conditions through quorum sensing (e.g., luxS and lsrA) and two-component systems (e.g., phoA and atoA). The enhanced TCA cycle, which provides electrons and energy for VFAs production and environmental adaptability, was more pronounced with biochar, ultimately leading to increased overall VFAs production. This work provides a deeper understanding about the impact of conductive materials on anaerobic fermentation and offers valuable direction for optimizing FW treatment.

204. 题目: Low-quality straw over high-quality straw preferred for mineral-associated organic matter formation
文章编号: N25052705
期刊: Geoderma
作者: Xiaofang Ji, Dengchun Xing, Xin Guan, Yugang Wang, Gilles Colinet, Wenting Feng
更新时间: 2025-05-27
摘要: The formation of mineral-associated organic matter (MAOM) from plant litter decomposition is crucial for climate change mitigation. However, the way in which plant litter of varying qualities influences MAOM formation and decomposition, particularly regarding the quantity of litter inputs, remains largely unclear. This study aimed to determine how the quality of straw, specifically low-quality wheat (Triticum aestivum L.) versus high-quality milk vetch (Astragalus sinicus L.), and its quantity (input level) affect MAOM formation and decomposition. We conducted a 420-day laboratory incubation experiment using low-quality wheat versus high-quality milk vetch straws added to artificial soil (pure quartz vs. soil with reactive minerals (sandy soil: 5 % clay, 10 % silt, and 85 % sand)) at input levels of 0, 3, 6, 18, 26, 31, and 35 g C kg−1 soil. Different from the Microbial Efficiency-Matrix Stabilization theory, our research indicates that adding low-quality wheat straw led to significantly greater MAOM content than high-quality milk vetch. Notably, the MAOM stabilization efficiency declined at high input levels (26, 31, and 35 g C kg−1 soil) for wheat than for milk vetch. This is further supported by the evidence that reactive minerals slowed the decomposition rate of low-quality wheat straw more effectively than that of high-quality milk vetch. Moreover, the lower C/N ratio of the MAOM fraction, the reduced C/N ratio of dissolved organic matter (DOM), and a higher fluorescence index of DOM (higher values indicating greater contribution of microbial sources) after adding milk vetch than adding wheat straw suggest the significant role of plant-derived organic matter in MAOM formation. Our findings disclose that reactive minerals preferentially protect low-quality litter over high-quality litter through direct interaction with plant-derived organic matter, providing a critical pathway for MAOM formation distinct from microbial assimilation. This study highlights the key role of low-quality straw in the efficient and long-term stabilization of soil C within agricultural practices.

205. 题目: Biochar mediated microbial synergy in Partial nitrification-anammox systems: enhancing nitrogen removal efficiency and stability
文章编号: N25052704
期刊: Frontiers of Environmental Science & Engineering
作者: Jingwei Fu, Yifei He, Hexiang Zhao, Hao Yang, Qian Li, Rong Chen, Yu-You Li
更新时间: 2025-05-27
摘要:

This study investigated the role of biochar in enhancing nitrogen removal efficiency (NRE) and stability in partial nitrification-anammox (PN/A) systems, focusing on its selective promotion of partial denitrification and maintaining the dynamic balance between AnAOB and denitrifying bacteria (DNB). The results showed that biochar enhances electron transfer, effectively reduced nitrate accumulation and significantly improved PN/A system NRE and stability. Under high ammonium conditions (800 mg/L), biochar increased NRE in the PN/A system to 83.58%, a 10% improvement over the anammox-control (A_CK). Additionally, partial denitrification contributed 8% more to total nitrogen removal in the anammox-biochar (A_BC) system. The porous structure and redox-active groups of biochar provided an ideal environment for key microorganisms, promoted microbial growth and increased specific anammox activity by approximately 1.25–1.46 times compared to A_CK, further enhancing microbial stability under fluctuating nitrogen loads. Biochar also enriched AnAOB and DNB communities, sustained their dynamic balance and improved system stability by promoting nitrogen removal related gene expression. Overall, biochar demonstrated great potential for improving PN/A system efficiency, optimizing wastewater treatment, and reducing energy consumption and emissions.

206. 题目: Soil organic carbon stabilization inside microaggregates within macroaggregates is the major mechanism of carbon sequestration under a long-term agroforestry system in the foot hills of the Indian Himalayas
文章编号: N25052703
期刊: Soil and Tillage Research
作者: Swarnashree Barman, Ranjan Bhattacharyya, Charan Singh, A C Rathore, Vibha Singhal, M Muruganandan, Anshuman Patel, Anshuman Das, S L Jat, P Jha, Avijit Ghosh, D R Biswas, Nayan Ahmed, Shrila Das, T K Das, Soora Naresh Kumar
更新时间: 2025-05-27
摘要: We used a new methodology to compute stabilized soil organic carbon (SOC) within the density fractions to evaluate the alterations in SOC in fine silty hyperthermicudic haplustalf following fifteen-years of agroforestry practices under cowpea (Vigna unguiculata L.)-toria (Brassica campestris L.) based cropping systems and turmeric (Curcuma longa L.) as ground cover crop. The objective of this long-term (15 years) experiment was to quantity the carbon content within soil aggregates as affected by agroforestry practices. The results indicated that in the surface soil (0–15 cm depth), plots with mulberry (Morus alba L.) + cowpea-toria (T7) had 58, 26 and 30 % higher total SOC in bulk soil than cultivated fallow land (T9) (6.76 g kg−1), sole planting of mulberry (T5) (8.47 g kg−1) and cowpea-toria system (T4) (8.21 g kg−1), respectively. Intra-aggregate associated particulate organic matter within the microaggregates inside macroaggregates (iPOM_mM) was maximum in plots under T7 and the value was 104 % higher than T5 and ∼90 % larger than T4 in surface soil layer. Light fraction inside microaggregates within macroaggregates (LF_mM) associated C was 18 % and 14 % more in T7 plots than T4 (13.34 g kg−1) and T5 (13.80 g kg−1) plots. Plots with T7 showed maximum stabilized C (5.63 g C/1000 g bulk soils) within iPOM_mM and the value was 152 % and 164 % higher than T4 (2.23 g C/1000 g bulk soil) and T5 (2.13 g C/1000 g bulk soils) plots and also had 86 % more stabilized C than T3 (3.02 g C/1000 g bulk soil) agroforestry system. About 49 % of the total stabilized C in the plots under T7 in the surface soil layer was there within the intra-aggregate particulate organic matter inside microaggregates within macroaggregates, suggesting intra-aggregate particulate organic matter formation inside microaggregates within macroaggregates was the major mechanism of C sequestration under the long-term agroforesty system in the Indian Himalayas. Morus alba L.-based agroforestry system (AFS) had more aggregates and total SOC within microaggregates inside macroaggregates which have more carbon sequestration potential in the foot hills of the Indian Himalayas. Thus, the T7 agroforestry system should be adopted for higher C stabilization.

207. 题目: Changes in soil properties shape how microbes mediate soil carbon sequestration under nitrogen addition
文章编号: N25052702
期刊: Journal of Cleaner Production
作者: Yansheng Cao, Tongbin Zhu
更新时间: 2025-05-27
摘要: The potential of soil carbon (C) sequestration driven by nitrogen (N) addition as a strategy for mitigating climate change has been widely discussed. However, the underlying mechanisms by which microbes facilitate the accumulation of soil organic carbon (SOC) under N addition are not fully understood. Current research often overlooks the contribution of increased microbial growth and activity to SOC accrual, and a comprehensive understanding of the key factors governing microbial-mediated C sequestration in soil is lacking. To address this knowledge gap, a global meta-analysis was conducted to investigate the effect of N addition on soil C sequestration. This analysis revealed distinct pathways for soil C sequestration. In negative-role systems, N-induced changes in heterotrophic respiration (HR) proved to be a more significant predictor of SOC response than N-induced changes in MBC (HR: P < 0.01; MBC: P > 0.05). Changes in soil pH emerged as the primary driver of HR fluctuations (P < 0.001). Conversely, in positive-role systems, N-induced changes in MBC played a central role in determining soil C storage (MBC: P < 0.001; HR: P > 0.05). N-induced changes in total N emerged as the most significant explanatory variable for MBC variations across various potential predictors (P < 0.001), while N-induced changes in soil pH exerted a secondary influence on these changes (P < 0.05). Our results revealed that N addition can contribute to SOC accrual not only by inhibiting microbial decomposition due to soil acidification, but also by stimulating microbial growth as a result of increased total N content. However, soil acidification may weaken the positive effect of total N on microbial growth. It is suggested that further research considers incorporating microbial growth and metabolism in individual microbial taxa to gain a better understanding of these mechanisms, and evaluates their regulation of soil C storage under altered N deposition.

208. 题目: Aggregate pore and shape properties were more strongly correlated to soil organic carbon in large aggregates: Evidence from a long-term management-induced soil carbon gradient
文章编号: N25052701
期刊: Geoderma
作者: Weijun Zhang, Lars J Munkholm, Richard J Heck, Christopher W Watts, Johannes L Jensen
更新时间: 2025-05-27
摘要: The interplay between soil structure and soil organic carbon (SOC) is complex and affects key soil functions. There is limited knowledge on how this relationship changes with the size of the structural unit studied. The objective of this study was to quantify the pore and shape characteristics of soil aggregates of varying sizes, and their relationships with SOC under different soil management regimes. Soils were sampled in March 2015 from the Highfield Ley-Arable Long-Term Experiment at Rothamsted Research. This experiment includes bare fallow, continuous arable rotation, ley-arable rotation, and grass treatments. A total of 24 aggregates from each treatment and size class (2–4, 4–8, and 8–16 mm) were subjected to X-ray micro-CT scanning at 40 μm voxel resolution. Results showed that permanent grass not only increased SOC accumulation, but also promoted pore connectivity of soil aggregates compared to bare fallow, regardless of aggregate size. Additionally, the pore and shape characteristics of larger aggregates (4–8 and 8–16 mm) were more sensitive to soil management compared to smaller aggregates (2–4 mm). The relationships between SOC and aggregate structural characteristics were strong for both 8–16 and 4–8 mm aggregates but weak for 2–4 mm aggregates. Furthermore, the responses of pore connectivity and sphericity to SOC increased with aggregate size. The results suggest that organic matter input plays an essential role in shaping aggregate structural characteristics and aggregate rearrangement (especially in larger aggregates).

209. 题目: Prediction of soil organic carbon stock along layers and profiles using Vis-NIR laboratory spectroscopy
文章编号: N25052615
期刊: Catena
作者: S Dharumarajan, C Gomez, C G Kusuma, R Vasundhara, B Kalaiselvi, M Lalitha, R Hegde
更新时间: 2025-05-26
摘要: There is a growing need to estimate soil organic carbon (SOC) stocks at both local and global scales. This study explores the use of Visible–Near Infrared (Vis-NIR) laboratory spectroscopy as an alternative to traditional wet chemistry methods for SOC stock estimation. Two approaches were tested: an indirect method, which uses Partial Least Squares Regression (PLSR) models to predict SOC content and bulk density separately and then multiplies them by measured layer depth; and a direct method, where PLSR models predict SOC stock per layer directly. The estimates were then aggregated to calculate the total SOC stock per profile. We evaluated both approaches using 361 samples from 84 soil profiles collected across three villages in Kerala, India. Two calibration scenarios were tested: (i) non-clustering, where 75 % of the dataset was used for calibration and 25 % for validation, and (ii) clustering, where models were trained on samples from two villages and validated on the third. The results showed that the indirect approach consistently outperformed the direct approach, both at the layer and profile scale. The non-clustering calibration scenario provided variable accuracy, with R2val values ranging from 0.52 (direct approach) to 0.70 (indirect approach). The clustering scenario produced more variable results depending on the calibration set used. Overall, this study confirms that Vis-NIR spectroscopy is a promising, rapid, non-destructive, and cost-effective method for SOC stock estimation. However, scaling up its application across agricultural landscapes will require substantial data collection and further methodological refinement.

210. 题目: Bacteriophages enhance the transformation of dissolved organic matter during vermicomposting of sludge
文章编号: N25052614
期刊: Bioresource Technology
作者: Licheng Zhu, Kui Huang, Tiegen Bai, Hui Xia
更新时间: 2025-05-26
摘要: Vermicomposting is an eco-friendly technology for treating sewage sludge, however its efficiency in transforming biological material is often constrained. This study investigates the potential of bacteriophages to enhance the transformation of dissolved organic matter (DOM) during sludge vermicomposting. Fresh dewatered sludge treated with bacteriophages (VP) were compared to untreated controls (CK) over a 30 days’ vermicomposting. The results showed that bacteriophage inoculation led to a 58.17 % reduction in dissolved organic carbon (DOC), significantly higher than the 10.67 % reduction in the CK group (P < 0.05). Additionally, the DOM stability indices in the VP treatment were significantly decreased by 30.95 % (P < 0.05), alongside an increased humification rate. Partial least squares path modeling (PLS-PM) revealed that bacteriophages played a pivotal role in accelerating DOM degradation by selectively lysing specific bacterial populations and altering DOM transformation pathways.

211. 题目: Molecular fingerprinting of dissolved organic matter during coagulation pretreatment of real textile printing and dyeing wastewater
文章编号: N25052613
期刊: Journal of Environmental Management
作者: Hualiang Feng, Zhangzhang Huang, Zhaoji Zhang
更新时间: 2025-05-26
摘要: The patterns and mechanisms of organic matter removal during coagulation treatment of textile printing and dyeing wastewater (TPDW) with different coagulants are not yet well understood. This study investigated the effects of coagulants on the pretreatment of real TPDW under varying pH and dosage conditions in single or dual coagulation systems. It focused on analyzing the molecular characteristics of organic compounds during coagulation treatment with ferric chloride (FeCl3), polyaluminum chloride (PAC), and a combination of FeCl3 and polyacrylamide (PAM) (FeCl3 + PAM), using Fourier transform ion cyclotron resonance mass spectrometry. The results revealed that the organic molecules removed by these coagulation systems were largely similar, particularly FeCl3 and FeCl3 + PAM, consisting mainly of CHOS and CHON compounds with mass-to-charge ratio (m/z) 300–600, and containing more carboxyl groups. These molecules exhibited higher values of H/C, O/C, m/z, nominal oxidation state of carbon (NOSC), and lower values of modified aromaticity index (AImod) and (double-bond equivalent (DBE)-O)/C, compared to those not removed. However, PAC removed CHO compounds with higher values of m/z, AImod, (DBE-O)/C, and lower NOSC, compared to FeCl3 or FeCl3 + PAM. Zeta potential and Fourier transform infrared spectroscopy analyses indicated that the mechanisms for organic matter removal include charge neutralization and bridge adsorption. FeCl3 + PAM may be the most cost-effective choice. This study provides molecular-level insights into the removal of organic matter during coagulation treatment of real TPDW, enabling more effective control of its organic pollutants.

212. 题目: Intensive input of labile carbon and mineral nitrogen enhancing the sequestration organic carbon across soil aggregates
文章编号: N25052612
期刊: Journal of Environmental Chemical Engineering
作者: Shixun Su, Jiajiang Lin, Zuliang Chen
更新时间: 2025-05-26
摘要: Soil carbon (C) cycling is strongly influenced by inputs of labile organic carbon (LOC) and mineral nitrogen (N), yet how these inputs interactively affect soil organic carbon (SOC) turnover remains poorly understood. This study investigates how glucose (as a LOC source) and two mineral N forms collectively regulate SOC dynamics at the aggregate scale. All treatments enhanced SOC storage, with glucose (CT), glucose + ammonium (CA) and glucose + nitrate (CN) increased SOC by 9.60 %, 7.38 % and 5.91 %, respectively. Elevated SOC aliphaticity under N amendments suggested enhanced microbial assimilation, particularly via fungal-dominated networks. Furthermore, organic carbon (OC) degradation genes were upregulated in the order: CT > CN > > CA, indicating that combined N and C inputs significantly mitigated SOC biodegradation. The decrease in readily oxidizable C under CA treatment implied greater microbial assimilation, with subsequent transformation into recalcitrant organic fractions. At the aggregate scale, CT predominantly increased SOC in large macro-aggregates, whereas CN and CA promoted greater SOC accumulation in small macro-aggregates and micro-aggregates. CN and CA also increased N-alkyl and methoxyl C in micro-aggregates, confirming enhanced N assimilation within these aggregates. In contrast to bacterial dominance, fungal contributions to SOC dynamics became progressively more important with decreasing aggregate size. Overall, glucose was protected in larger aggregates during macro-aggregates formation, while microbial assimilation promoted SOC sequestration in smaller aggregates. These findings advance our understanding of SOC transformation under C and N interactions, providing novel insights for optimizing SOC sequestration via strategic organic/inorganic input management.

213. 题目: Novel Fe-Mn modified self-nitrogen biochar composite: Synergistic adsorption-reduction mechanisms for enhanced Cr(VI) removal in aquatic systems
文章编号: N25052611
期刊: Separation and Purification Technology
作者: Li Zhang, Yuwei Tang, Yuting Zhang, Weibin Sun, Zihao Yang, Jinchunzi Li, Shuang Liang, Jing Zhou
更新时间: 2025-05-26
摘要: This study employed mango kernel polyphenols as green reductants to synthesize a novel Fe-Mn bimetallic-modified biochar derived from soy sauce residue (SSR), systematically investigating its performance and mechanisms for aqueous hexavalent chromium (Cr(VI)) removal. Comprehensive characterization through scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffractometer (XRD), Brunauer-Emmett-Teller (BET), and Fourier transform infrared spectroscopy (FT-IR) confirmed the successful loading of Fe-Mn oxides with optimized surface functionality. Batch experiments revealed maximum Cr(VI) removal efficiency (99.96 % within 120 min) at pH 2.0 using the composite with Fe/Mn molar ratio of 1:2. The intra-particle diffusion model and the pseudo-second order (PSO) kinetic model provided a more accurate description of Cr(VI) removal mechanism. The adsorbent demonstrated strong interference resistance against common cations (Na⁺, K⁺, Ca²⁺, Mg²⁺) and low-concentration anions (CO₃²⁻, SO₄²⁻). Fe/Mn-SRB0.5 exhibited excellent operational stability and reusability, retaining 94.32 % of Cr(VI) removal efficiency after five experimental cycles. Mn-mediated Cr(VI) reduction proceeded through direct electron transfer or Fe-synergized reduction. Electrostatic attraction, multi-components redox reactions, and complexation collectively governed Cr(VI) removal. This study prepared a functionalized composite with high efficiency, stability, and sustained reusability that possessed promising potential in improving Cr(VI) polluted environment.

214. 题目: The sources and burial fluxes of sedimentary organic carbon from the intensive mariculture zone in Haizhou Bay, China
文章编号: N25052610
期刊: Marine Pollution Bulletin
作者: Liushuyi Tan, Yi Liu, Jeffrey S Ren, Jihong Zhang
更新时间: 2025-05-26
摘要: The rapid development of mariculture would cause a considerable impact on the coastal carbon cycle. For investigating the source and contribution of mariculture to sedimentary organic matter, the composition of sediment cores in Haizhou Bay were analyzed, including 210Pbex activity, sedimentary total organic carbon (TOC), total nitrogen (TN), the stable carbon (δ13C) and nitrogen (δ15N) isotopic composition. The sediment accumulation rate in mariculture area varied between 1.7 and 2.8 cm·a−1, which is significantly higher than in control site. The results of the MixSIAR isotope mixing model indicated that shellfish biodeposits and soil organic matter are the primary contributors of sedimentary organic matter (SOM), while marine phytoplankton and seaweeds played a lesser role in the study area. The contribution of shellfish biodeposits to SOM in SF-1, SF-2 and BS were 4.1–36.65 %, 4.7–50.31 % and 5.2–19.0 %, respectively. The terrestrial source were the main contributors in the early years, have been affected by the impact of mariculture activities, and their contribution has gradually declined. The OC burial fluxes from shellfish biodeposits (BFbiodepositis) in SF-1 (6.17–23.82 g·m−2·a-1), SF-2 (7.62–79.71 g·m−2·a−1) and BS (2.9–15.25 g·m−2·a−1) tended to increase with the increasing scale of mariculture. Intensive shellfish mariculture influenced the sediment carbon sources and burial fluxes in coastal organic carbon cycles.

215. 题目: Exploring exopolysaccharide production from sugarcane bagasse: Mechanisms and processes involving Leuconostoc mesenteroides
文章编号: N25052609
期刊: Chemical Engineering Journal
作者: Yi Yang, Ziwen Wang, Zehai Chen, Yang Qiu, Dan Zhao, Renpeng Du, Jingping Ge, Wenxiang Ping
更新时间: 2025-05-26
摘要: Sugarcane is a lucrative global crop and a major source of sugar, generating large quantities of bagasse, which contributes to solid waste pollution. Additionally, the bagasse output is increasing yearly, further worsening this environmental challenge. Therefore, in this study, we focused on the high-value usage of sugarcane bagasse and produced a novel exopolysaccharide (EPS) by fermentation of sugarcane bagasse under open conditions using Leuconostoc mesenteroides DRP105, explored the microbial metabolism and microbial interactions during the whole fermentation process, to reveal the potential fermentation mechanism involved. The result showed that the highest level of EPS was 11.29 ± 0.25 g/L at 24 h, and the molecular weight of EPS was 5.21 × 10⁵ Da, which consisted of glucose and mannose 3:2. EPS showed lamellar stacking and formed a compact block structure. Moreover, EPS showed significant thermal stability with a degradation temperature of 312.72°C. EPS also exhibited significant probiotic and emulsifying properties. Metabolome and microbial community analyses revealed that the pre-existing Ln. mesenteroides DRP105 was able to use sucrose for growth and metabolism, and the later bacteria of the genera Burkholderia-Caballeronia-Paraburkholderia, Ralstonia and Variovorax were able to decompose lignocellulose to provide carbon source for the growth metabolism of Ln. mesenteroides DRP105 and promote EPS synthesis. These findings not only reduce the production cost of EPS, but also expand its application scope in the industrial field, providing strong support for the sustainable development of the circular economy.

216. 题目: Differentiating estuarine dissolved organic matter composition by unsupervised and supervised machine learning
文章编号: N25052608
期刊: Water Research
作者: Zhe-Xuan Zhang, Arnaud Huguet, Zoé Hayet, Edith Parlanti
更新时间: 2025-05-26
摘要: Differentiating the composition of Dissolved Organic Matter (DOM) in estuaries is a major environmental concern, as the DOM characteristics are closely linked to biogeochemical and ecological considerations (e.g. water properties and trophic cycling). However, tracing the spatiotemporal variations of estuarine DOM is challenging due to multiple sources and complex transformation processes. Here, we investigate the dynamics of estuarine DOM by analyzing the optical properties of DOM through UV-Visible absorbance and fluorescence spectroscopy, while also capturing the variability of DOM using machine learning algorithms and explainable artificial intelligence. To this aim, we collected sub-surface water samples (n=249) from a human-impacted estuary with intense industrialization and urbanization in France (Seine Estuary) across distinct land use characteristics in contrasting hydrological conditions. We then applied unsupervised and supervised machine learning techniques to analyze the optical properties of DOM, which were determined by UV–Visible absorbance and Excitation-Emission Matrix (EEM) fluorescence spectroscopy combined with parallel factor analysis (PARAFAC). Our results show that unsupervised machine learning (K-means clustering) captures the spatial variabilities of DOM, identifying three distinct estuarine zones based on pronounced spatial variations of several DOM optical parameters. Supervised machine learning (Light Gradient Boosted Machine, LightGBM) further validates the rationality of the defined zonation. Subsequently, explainable artificial intelligence based on SHapley Additive exPlanations (SHAP) analysis shows that DOM in each zone has specific characteristics. Our model indicates that DOM in the Seine Estuary is primarily influenced by high molecular weight materials and autochthonous contributions in the upper estuary (zone I). The dominant contribution to DOM in the mid-estuary (zone II) comes from autochthonous and aromatic material as well as transformation and (photo)degradation products. Lower estuary (zone III) is mainly characterized by aromatic DOM (subject to photodegradation), low molecular weight compounds, autochthonous DOM, as well as transformation and (photo)degradation products. Overall, this study presents a workflow for differentiating the composition of DOM, tracing the variability and dynamics of DOM along the land-to-sea continuum, and elucidating the involved processes. The approach developed in the Seine Estuary has significant implications for environmental management and can be adapted to other land-sea continuums.

217. 题目: Combining temperature ramp dry combustion and mid-infrared spectroscopy for enhanced soil organic carbon characterisation
文章编号: N25052607
期刊: Geoderma
作者: Lewis Walden, Raphael A Viscarra Rossel
更新时间: 2025-05-26
摘要: Soil organic carbon (SOC) is comprised of a complex mixture of plant and microbial-derived compounds with varying chemical compositions and stability. Understanding these components is crucial for modelling SOC turnover and stability. Conventional fractionation methods moslty use physical or chemical separations, but techniques such as mid-infrared (MIR) spectroscopy and thermal ramp dry combustion (TRDC) offer complementary, rapid approaches for SOC characterisation. This study integrates MIR spectroscopy and TRDC to characterise plant-derived compounds in soils. Using soils dosed with six plant-derived compounds (cellulose, lignin, starch, pectin, xylose, and biochar), we investigated their thermograms and MIR spectra. Each compound exhibited unique thermal decomposition peaks and MIR absorptions, reflecting their distinct chemical structures and oxidative stability. Correlation analyses revealed strong relationships between thermal peaks and MIR features. Models that combined MIR and TDRC spectra could estimate cellulose (ρc=0.92), biochar (ρc=0.95), pectin (ρc=0.77) and starch (ρc=0.87). Our findings show the potential for combining MIR spectroscopy and TRDC to characterise SOC chemical composition. By identifying distinct thermal and spectral features of plant-derived compounds, the combined approach could identify contributions of plant-derived compounds to labile and stable carbon pools, for enhancing our understanding of SOC decomposability. These methods may provide new insights into SOC turnover and stability mechanisms when applied to fractionated soils.

218. 题目: Characteristics, seasonal variations and major sources of underivatized free amino acids in PM2.5 at a rural coastal site in Qingdao, China
文章编号: N25052606
期刊: Environmental Pollution
作者: Sajid Kamal, Xinfeng Wang, Mingxuan Liu, Ayesha Shakoor, Mingyang Li, Jawad Ali, He Meng, Wei Jiang, Jabir Hussain Syed
更新时间: 2025-05-26
摘要: Free amino acids are an important class of organic nitrogen compounds found in aerosols that influence atmospheric chemistry, biological activity and human health. However, there is a lack of comprehensive understanding of their variation characteristics in rural coastal areas of northern China and the major sources of both anthropogenic and biogenic activities remain unclear. Field sampling and chemical analyses were conducted in three seasons at a rural coastal site in Qingdao. Using an Agilent 6470B Triple Quadrupole LC-MS, seven key underivatized free amino acids (UFAAs) were quantified, including glycine (Gly), leucine (Leu), isoleucine (Ile), serine (Ser), proline (Pro), alanine (Ala) and phenylalanine (Phe). Underivatized free amino acid concentrations and composition profiles exhibited distinct seasonal variations, with the highest mean concentrations in summer (171 ± 197 pmol m^-3), followed by spring (104 ± 146 pmol m^-3) and autumn (103 ± 123 pmol m^-3). Gly dominated the UFAA pool, contributing 49% in summer and 54% in autumn, whereas Leu dominated in spring, accounting for 37%. Correlation analysis indicated potential relationships with temperature, ozone and CO, whereas the positive matrix factorization (PMF) model identified five major sources; biomass burning, terrestrial and marine sources (such as agricultural activities and sea spray), microbial contributions, plankton emissions and secondary processes. Notably, biomass burning and terrestrial-marine sources substantially contributed to UFAAs, emphasizing the need for closer attention to biomass burning and biogenic emissions in rural coastal areas of northern China. These findings provide valuable insights into the composition, seasonal variability and source contributions of UFAAs to PM_2.5.

219. 题目: Origin of composite fibrous carbonate veins in Middle Jurassic ultra-low-ash coal, Ordos Basin, China: Insights on the interaction between organic carbon and inorganic carbonates after peat burial
文章编号: N25052605
期刊: Applied Geochemistry
作者: Jintian Zheng, Shifeng Dai, Victor P Nechaev, David French, Ian T Graham, Na Wang, Pan Yang, Shuai Kang, Mengda Yao, Yang Liang
更新时间: 2025-05-26
摘要: Valuable geological information on coal is contained within both the organic and inorganic constituents. Buried organic matter and precipitated carbonate minerals, as key elements of the lithospheric carbon reservoir, raise questions about whether their co-occurrence in coal is coincidental or reflects an underlying connection. Authigenic carbonate minerals in coal exhibit diverse species (e.g., siderite, calcite, and the ankerite-dolomite series) and morphologies (e.g., coal balls; nodules; and cell-, cleat- and fracture-filling forms), reflecting various formation processes during coalification. Fibrous carbonate veins in black shales consist of elongated calcite crystals with large aspect ratios (a rare calcite habit), and are associated with hydrocarbon fluid activity. However, the identification, formation mechanism, and material sources of fibrous carbonate veins within coal remains unclear. To resolve this problem, detailed petrographic, mineralogical, and geochemical analyses were conducted on the middle Jurassic No. 2(2) coal of the Ordos Basin, China, including stable isotopic analysis of carbon and oxygen in composite carbonates excluding siderite. The No. 2(2) coal seam is classified as an ultra-low-ash, super-low-sulfur, and high volatile B bituminous coal, according to the Chinese national standards GB/T 15224.1-2018, GB/T 15224.2-2021, and ASTM Standard D388-23, respectively. It contains abundant fusinite and semifusinite fragments dispersed in collodetrinite. Compared with average world coals, only Sr in the coal is slightly enriched. The carbonates in the coal (33.5 %; low temperature ash basis) consist of calcite, ankerite, and siderite. The values of δ13CVPDB and δ18OVPDB associated with composite carbonate veins (calcite and ankerite) range from −34.87 ‰ to −11.43 ‰ and from −14.66 ‰ to −10.84 ‰, respectively. Two types of high-ash yield intervals (Si-rich and Ca-rich) were identified within the low-ash coal seam. The Si-rich benches are attributed to the influx of Si–Al-rich fluids during peat accumulation. Composite carbonate veins, which formed during coalification, represent another source for inorganic matter in high-ash intervals (Ca-rich). Optical and electron microscope observations, together with carbon-oxygen isotopic analyses, indicate that overpressurised fluids from coal maturation and methane oxidation led to in situ coal fracturing, followed by the formation of composite fibrous carbonate veins and crack-seal structures in low-ash coal. Based upon these results, a model for the formation of fibrous carbonate veins within low-ash coal from the Cuijiagou mine is proposed to facilitate an understanding of the carbon transformation from organic matter to minerals after peat burial.

220. 题目: Vegetation restoration enhances soil organic carbon accumulation in Southwest China’s karst region: The role of aggregation, calcium, and microbes
文章编号: N25052604
期刊: Catena
作者: Jiacheng Lan, Yongxiang Jiang, Mingzhi Huang
更新时间: 2025-05-26
摘要: Vegetation restoration promotes soil organic carbon (SOC) accumulation through physical aggregate protection, mineral chemical stabilization, and microbial-driven mechanisms. However, the quantitative contributions of these three factors to SOC stocks, including their interactions and influences, remain poorly understood. This study investigated the influence of soil aggregate fractions: large macroaggregates (>2 mm), small macroaggregates (2–0.25 mm), microaggregates (0.25–0.053 mm), and silt + clay fractions (<0.053 mm), aggregate-associated organic carbon (OC), minerals, and microbial variables on SOC stocks and their relative contributions following cropland restoration. Soil samples were collected from depths of 0–10 cm across the croplands and two cropland restoration systems: a secondary forest and a plantation forest. The four aggregate-associated OC fractions significantly contributed to SOC stocks (p < 0.05). Variations in each aggregate-associated OC fraction were linked to changes in the soil aggregate fractions, exchangeable calcium (Ca), bacterial abundance, and community compositions. In addition, aggregates, minerals, and microbes explained 90.1 % of the variance in the SOC stocks. The SOC stock was primarily influenced by the interactive effects of aggregates, microbes, and minerals (34.2 %), aggregates alone (27.2 %), and aggregate–microbial (22.3 %) interactions. Our findings underscore the critical role of soil bacterial variables in influencing aggregate-associated OC and stabilizing SOC, whereas soil-exchangeable Ca plays a significant and indispensable role in mineral protection and the regulation of SOC stocks. These results highlight that the SOC protection and stabilization mechanisms following vegetation restoration arise from the interplay and interdependence of physical aggregate protection, soil mineral binding, and microbial metabolic processes in this karst region.